Shorten commit hashes

Author: nobu

lib/rdoc/parser/changelog.rb

@@ -211,7 +211,7 @@ module Git
     def parse_entries
       entries = []
 
-      @content.scan(/^commit\s+(\h+)\n *Author: *(.+)\n *Date: *(.+)\n\n((?: {4}.*\n+)*)/) do
+      @content.scan(/^commit\s+(\h{20})\h*\n *Author: *(.+)\n *Date: *(.+)\n\n((?: {4}.*\n+)*)/) do
         entry_name, author, date, entry_body = $1, $2, $3, $4.gsub(/^ {4}/, '')
         if /(\d+)-(\d+)-(\d+) (\d+):(\d+):(\d+) *([-+]\d\d)(\d\d)/ =~ date
           time = Time.new($1, $2, $3, $4, $5, $6, "#{$7}:#{$8}")

test/rdoc/test_rdoc_parser_changelog.rb

@@ -280,7 +280,7 @@ def test_parse_entries_git
 ChangeLog
 
     expected = [
-      [ "709bed2afaee50e2ce803f87bf1ee8291bea41e3",
+      [ "709bed2afaee50e2ce80",
        [ "git <svn-admin@ruby-lang.org>",
          "2021-01-21 01:03:52 +0900",
          "* 2021-01-21 [ci skip]\n"]]]